Genome-Wide Identification and Expression Profiling Analysis of the Galactinol Synthase Gene Family in Cassava (Manihot esculenta Crantz)

Abstract

Galactinol synthases (GolSs) are the key enzymes that participate in raffinose family oligosaccharides (RFO) biosynthesis, which perform a big role in modulating plant growth and response to biotic or abiotic stresses. To date, no systematic study of this gene family has been conducted in cassava (Manihot esculenta Crantz). Here, eight MeGolS genes are isolated from the cassava genome. Based on phylogenetic background, the MeGolSs are clustered into four groups. Through predicting the cis-elements in their promoters, it was discovered that all MeGolS members act as hormone-, stress-, and tissue-specific related elements to different degrees. MeGolS genes exhibit incongruous expression patterns in various tissues, indicating that different MeGolS proteins might have diverse functions. MeGolS1 and MeGolS3–6 are highly expressed in leaves and midveins. MeGolS3–6 are highly expressed in fibrous roots. Quantitative real-time Polymerase Chain Reaction (qRT-PCR) analysis indicates that several MeGolSs, including MeGolS1, 2, 5, 6, and 7, are induced by abiotic stresses. microRNA prediction analysis indicates that several abiotic stress-related miRNAs target the MeGolS genes, such as mes-miR156, 159, and 169, which also respond to abiotic stresses. The current study is the first systematic research of GolS genes in cassava, and the results of this study provide a basis for further exploration the functional mechanism of GolS genes in cassava.

Characterization of raffinose metabolism genes uncovers a wild Arachis galactinol synthase conferring tolerance to abiotic stresses

“…The phylogenetic analysis of putative RFO-related proteins from Fabaceae, including these five enzyme families identified in wild Arachis, showed a clear subdivision within each family, supported by high bootstrap values. This clustering, based on phylogenetic proximity, was related to the intron/exon organization of the corresponding Arachis genes, as previously observed for other plant species [8][9][10] . Similarly to the conservation of gene structure, amino acid sequences were highly conserved too, for example, the hydrophobic pentapeptide (APSAA), characteristic of the GolS family 42 , was found for all the proteins from A. duranensis and A. ipaënsis, as well as other conserved motifs in the different enzyme families.…”

“…However, over the 150 min time frame of the experiment, increased levels of GolS transcripts seem to be insufficient to allow the observation of the expected increase in the expression of the downstream genes involved in the subsequent steps of RFO biosynthesis ( RS and STS ). Similar comprehensive expression profiles of GolS, RS and STS genes were observed in response to water-deficit treatments in S. indicum , M. esculenta and G. max 9 , 10 , 15 . Also, genes involved in RFO catabolism ( AGAL and BFLUCT ) were downregulated in response to this severe water-limited condition.…”

“…RFOs are part of the molecular network activated by plants in response to a range of environmental stresses and currently emerge as key components in stress tolerance, acting as osmoprotectants, antioxidants and signaling molecules 2,4 . Due to their importance, the principal enzymes involved in the first steps of RFO biosynthesis (GolS, RS and STS) have been thoroughly studied at the genome-wide scale in many plant species [8][9][10][11][12]15 . However, little attention has been given to the enzymes involved in RFO catabolism, such as AGAL and BFLUCT.…”

“…Galactinol and RFOs are ubiquitous in plants and the genes coding for enzymes involved in their metabolism have been identified and characterized in some crop species, including Zea mays 8 , Manihot esculenta 9 , Sesamum indicum 10 , Solanum lycopersicum 11 and Malus × domestica 12 . Whilst RFOs are major soluble sugars that are second only to sucrose in abundance in mature legume seeds 13 , very little is known about the genes involved in raffinose metabolism in Fabaceae species, with few examples described in Cicer arietinum and Glycine max 14 , 15 .…”

Overexpression of Cassava MeAnn2 Enhances the Salt and IAA Tolerance of Transgenic Arabidopsis

“…Cassava ( Manihot esculenta Crantz) is an important starch crop which has good tolerance to drought and barren soil [ 36 , 37 ]. In this study, we successfully cloned the cDNA sequence of an annexin gene MeAnn2 , from cassava SC8 (South China No.…”